This application is in response to PA-07-180, School-Based Interventions to Prevent Obesity. Childhood obesity has reached epidemic proportions, threatening the health and well-being of our nation's children, American life-expectancy, and the future viability of our health care system. Schools offer an important venue to test obesity prevention programs. The Institute of Medicine's (IOM) Committee on Prevention of Obesity in Children and Youth recommends that schools provide annual body mass index (BMI) assessments and make this information available to parents (2005). Some schools have begun to assess children's BMI as part of their health screenings. However, school-based BMI screening is controversial and its impact on parent behavior and child health is unknown. The primary specific aim of this application is to conduct a randomized controlled study to assess the impact of annual school-based BMI screening (with parent notification of the child's BMI results) on child health (BMI percentile and fitness) and parent behavior, namely utilization of three school- based wellness programs: (1) a child after-school exercise program;(2) expanded health assessments;and (3) a health promotion website. A second specific aim is to (1) document any decline in fitness and increase in BMI percentile associated with the summer break and (2) examine the impact of providing parent feedback on the child's BMI percentile and fitness progress over the school year on maintenance of these gains during the summer months. A third specific aim is to document the differential impact, if any, of BMI screening on ethnic-minority children's health and parent behavior, controlling for other demographic factors including socioeconomic status (SES) (indicated by child eligibility for the free or reduced price lunch program), gender, and age. Twelve elementary schools froman ethnically/racially diverse school system will be randomized to one of three conditions over a three year period: annual BMI assessment with parent notification (BMI Screening);annual BMI assessment with parent notificationplus a year-end progress report on child BMI and fitness (BMI Screening plus Progress Report);and BMI assessment with no parent notification (BMI Surveillance control), which represents current practice in Leon County Schools and the state of Florida. Child health will be indexed by BMI percentile and fitness assessed in the fall and spring of each school year. Parent behavior will be indexed by child attendance in the after-school exercise program, parent consent to expanded child health assessments, and family utilization of the health promotion website. This application is responsive to PA-07-180, School-Based Interventions to Prevent Obesity because it (1) represents a partnership between a school systemand an academic institution, (2) collects baseline data on children in elementary schools, (3) devises and implements an intervention in a controlled fashion, and (4) assesses outcome variables for varying lengths of time post-intervention. Public Health Relevance: Childhood obesity has reached epidemic proportions, threatening the health and well-being of our nation's children, American life-expectancy, and the future viability of our health care system. Although, the Institute of Medicine's Committee on Prevention of Obesity in Children and Youth (2005) recommends that schools conduct yearly body mass index (BMI) assessments with parent notificationof results, there are few research studies examining the impact of school-based BMI screening. This study is designed to fill this gap by assessing the impact of school-based BMI screening with parent notification of the child's BMI results on child health and parent behavior.